It is absolutely shocking. No one ever guessed. No one even suspected. No one knew the darkest secret, the chill in the air, the poison in the communion chalice of Justin Welby's tenure of episcopal office. Lambeth Palace has been quick to make everything public, as is its longstanding policy when such serious allegations against clergy are made. They are committed to equality of justice and transparency: there are no exceptions; there can be no whiff of a cover-up.

Justin Welby's children and grandchildren are dismayed, horrified, mortified. They loved and trusted the man whom the world knew as Archbishop Justin, but they simply called 'Dad' and 'Grandpa', little knowing that to one boy (at least) he was the shadowy, dark figure at the top of the stairs who used and abused a child (or was it children?) for his own gratification.

And the boy -- known as 'Nick' to protect his identity -- described those stairs so accurately: five or six of them, cold and grey, then a left turn up to what seemed like an ante-room, with dark panelled walls and a stone fireplace which had a desk in front of it. A small ink-sketched portrait hung above that desk; random antique chairs scattered around. To the left of the desk was a leaded window and then a little further along was a heavy curtain which, when drawn back, led to a balcony overlooking the chapel altar, where the nightmare would wait. The memory is slightly distorted -- it has been so long -- but the details are there. For those who know Lambeth Palace, 'Nick' had described the path up to the study in Cranmer's Tower.

Justin Welby's children are adamant that their father never used this space, but 'Nick' is a very credible witness; a person of profound dignity and integrity. Why would he fabricate such evil slander? Besides, a psychiatric report supports his testimony: there is no evidence of personality disorder or any reason to believe this to be a case of false memory.

The Archbishop of Canterbury, the Most Rev'd and Rt Hon Martine Percival, has herself presided over a "very thorough" (her words) inquiry into these allegations. Independent reports have been commissioned and considered. She said: "The survivor of Welby's abuse must be taken seriously." She emphasised that she had no desire at all to damage Justin Welby's reputation, and has reassured the church and the world that the gospel of Christ is the safest of spaces, and that safeguarding children is foundational to her mission.

Archbishop Martine was full of praise for her predecessor's immense achievements, making it clear that she feels she owes him her current position. In a further written statement she said:

Archbishop Justin Welby is one of the great Anglican heroes of the 21st century, and a personal hero of mine for his commitment to gender equality and justice for all. The decision to publish his name was taken with immense reluctance, and all involved recognised the deep tragedy involved.

In all cases of sexual abuse, including those where the person complained about is dead, we are utterly committed to seeking to ensure just outcomes for all. The complaint about Archbishop Justin Welby does not diminish the importance of his great achievements.

We realise that a significant cloud is left hanging over his name. Let us therefore remember his 'Reform and Renewal' programme, which helped to turn the tide in church decline; his 'Thy Kingdom Come' initiative, which turned the whole Christian world toward prayer; his establishment of the Community of St Anselm, through which many thousands of young disciples of Christ have learned to love and serve their Lord; his steady hand of national leadership following the death of Her Gracious Majesty Queen Elizabeth II, and his distinguished presiding over the Coronation of the new King, who was crowned Defender of the Faith -- the Christian Faith -- at Archbishop Justin's insistence. Let us not forget his moral stand against persecution, discrimination and human suffering; his personal risks in the cause of peace and reconciliation, and his long service in the cause of conflict resolution.

No human being is entirely good or bad. Archbishop Justin was in many ways a hero. He is also accused of great wickedness. Good acts do not diminish evil ones, nor do evil ones make it right to forget the good. Whatever is thought about the accusations, the whole person and whole life should be kept in mind.

The Welby family aren't entirely happy about this 'kangaroo court': they feel cheated of justice in a church seemingly more obsessed with its national reputation and damage limitation than with truth-seeking or justice-serving. They have asked why Canon David Porter was not interviewed in relation to these appalling allegations. As Justin Welby's chief of staff throughout his time at Lambeth Palace, Canon Porter was at the Archbishop's side virtually 24/7. He might be in his 90s, but isn't his primary testimony important? Might he not possess diaries of dates and meetings which could shine some light on the plausibility of these allegations? And what about the Archbishop's chaplains throughout his period of office? Why have they not been asked to give evidence in defence of the man they served faithfully and honourably, in very close proximity, believing him to be a faithful and honourable man?

And what about the Archbishop's wife, Caroline? Was their marriage a sham; a ruse to conceal homosexual urges and paedophilic inclinations? Did she ever speak of this to anyone? Did none of her closest friends and confidants really know absolutely nothing? How could this even be possible?

Archbishop Martine Percival has made it clear that her inquiry was not asked to determine whether or not Nick's devastating memories of decades ago could be verified: she was adamant that the victim must be taken seriously. "Paedophiles almost always have form," she explained, "and offenders like Welby are likely to re-offend." She made it clear that other survivors of "Welby's wickedness" (her words) behind closed doors may be afraid to come forward or speak out, and so this very thorough inquiry is to reassure them that they will be heard and that this Archbishop will listen to them sympathetically.

"If Archbishop Justin were alive today, he would certainly be arrested," she added, omitting to remind her audience that an arrest does not signify guilt. She has reassured the Welby family and all those who knew and loved the late Archbishop that her investigation was not only objective and fair, but proper and robust, and that "on the balance of probabilities," she said, "it is reasonable to believe Nick."

So Nick has been paid £180,000 compensation, and received a letter of apology from the church. Nothing more can be said for legal reasons.

So now a significant cloud broods over the name of Justin Welby -- one of disgrace, shame and sin. But please remember that the wicked acts of which he is accused should not cause us to forget the immense good he did. He was undeniably a man of rich complexity, ecclesial nuance and great pastoral abundance. As Archbishop Martine has said: "The whole person and whole life should be kept in mind."

Yet what an injustice it must seem to his children and grandchildren, and indeed to all those who remember his passion for peace and his zeal for the gospel, that henceforth he is to be known as Unjustin Welby -- the archbishop who, on the balance of probabilities, molested Nick up Cranmer's Tower.